The Channel (Chunnel) Tunnel

Dr. R Kuberan, Ms. Sudeshna Mukherjee

The idea to build a tunnel linking England and France first came
about in 1802. Throughout the years many people had ideas and
plans to link the two countries but it took more than 180 years
to make it actually happen. The privately financed project, owned by
Eurotunnel began in 1986. This lofty project would build an undersea leg
that spans the English Channel between England and France.
The project was completed in May of 1994 and opened for passenger
service that November. For travellers and the haulage industry, the
Channel Tunnel dramatically shortening travel time between London
and Paris.
Since commercial services started more than 366 million passengers
have traveled through the Channel Tunnel, the equivalent to five times
the population of the United Kingdom. Some facts and specifications
of this tunnel:

1. The Channel Tunnel is 31.4 miles long, making it the 11th longest
tunnel in use (the longest is the Delaware Aqueduct, at 85.1 miles),
and the fourth longest used by rail passengers. It has the longest
undersea portion of any tunnel in the world (23.5 miles).
2. The project cost £4.65 billion (equivalent to £12 billion today), 80
per cent more than expected. Construction took six years (1988-
1994).
3. It was recognized as one of the “Seven Wonders of the Modern
World” by the American Society of Civil Engineers, alongside the
Empire State Building, the Itaipu Dam in South America, the CN
Tower in Toronto, the Panama Canal, the North Sea protection
works in the Netherlands, and the Golden Gate Bridge in San
Francisco.
4. The first proposal for a tunnel under the Channel was put forward
by Albert Mathieu, a French engineer - it included an artificial island
half-way across for changing horses.
5. At the height of construction, 13,000 people were employed. Ten
workers - eight of them British - were killed building the tunnel.
6. Englishman Graham Fagg and Frenchman Phillippe Cozette carried
out the ceremonial break through on December 1, 1990.
7. They didn’t quite meet in the middle - the English side tunneled the
greater distance.
8. The average depth of the tunnel is 50 metres below the seabed,
and the lowest point 75 metres below. Much of the chalk marl spoil
bored on the English side was deposited at Lower Shakespeare Cliff
in Kent, now home to the Samphire Hoe Country Park.
9. There are actually three tunnels down there - two for trains and a
smaller service tunnel that can be used in emergencies.

10. Up to 400 trains pass through the tunnel each day, carrying an
average of 50,000 passengers, 6,000 cars, 180 coaches and
54,000 tonnes of freight.
11. Three fires have occurred (in 1996, 2006 and 2012) inside the
tunnel that was significant enough for it to close. The most serious,
on November 18, 1996, damaged 500 meters of the tunnel,
affecting operations for six months. An automatic fire dousing
system has now been installed.
12. A number of train failures have occurred. On December 18, 2009,
five Euro star trains broke down, trapping 2,000 passengers for
16 hours without power, and many without food or water.
13. In 2014 a record 21 million passengers were transported between
Britain and France using the tunnel - up from 7.3 million in 1995,
its first full year in operation.
14. Shuttle trains are 775 meters long - the same as eight football
pitches.

15. The lining of the tunnel is designed to last for 120 years.
16. It takes around 35 minutes to travel the length of the Channel Tunnel.
Surveying undertaken in the 20 years before construction confirmed
earlier speculations that a tunnel could be bored through a chalk marl
stratum. The chalk marl is conducive to tunnelling, with impermeability,
ease of excavation and strength. The chalk marl runs along the entire
length of the English side of the tunnel, but on the French side a length
of 5 kilometres (3 mi) has variable and difficult geology. The tunnel
consists of three bores: two 7.6-metre (25 ft) diameter rail tunnels,
30 meters (98 ft) apart, and 50 kilometres (31 mi) in length with a
4.8-metre (16 ft) diameter service tunnel in between. The three bores
are connected by cross-passages and piston relief ducts. The service
tunnel was used as a pilot tunnel, boring ahead of the main tunnels to
determine the conditions. English access was provided at Shakespeare
Cliff, French access from a shaft at Sangatte. The French side used five
tunnel boring machines (TBMs), the English side six. The service tunnel
uses Service Tunnel Transport System (STTS) and Light Service Tunnel
Vehicles (LADOGS). Fire safety was a critical design issue.
Between the portals at Beussingue and Castle Hill the tunnel is 50.5
kilometres (31 mi) long, with 3.3 kilometres (2 mi) under land on the
French side and 9.3 kilometres (6 mi) on the UK side, and 37.9 kilometres
(24 mi) under sea. It is the third-longest rail tunnel in the world, behind
the Gotthard Base Tunnel in Switzerland and the Seikan Tunnel in Japan,
but with the longest under-sea section. The average depth is 45 metres
(148 ft) below the seabed. On the UK side, of the expected 5 million
cubic metres (6.5×106 cu yd) of spoil approximately 1 million cubic
metres (1.3×106 cu yd) was used for fill at the terminal site, and the
remainder was deposited at Lower Shakespeare Cliff behind a seawall,
reclaiming 74 acres (30 ha) of land. This land was then made into the
Samphire Hoe Country Park. Environmental impact assessment did not
identify any major risks for the project, and further studies into safety,
noise, and air pollution were overall positive. However, environmental
objections were raised over a high-speed link to London.
Working from both the English side and the French side of the
Channel, eleven tunnel boring machines or TBMs cut through chalk
marl to construct two rail tunnels and a service tunnel. The vehicle
shuttle terminals are at Cheriton (part of Folkestone) and Coquelles,
and are connected to the English M20 and French A16 motorways
respectively. Tunnelling commenced in 1988, and the tunnel began
operating in 1994. In 1985 prices, the total construction cost was

£4.650 billion (equivalent to £13 billion today), an 80% cost overrun.
At the peak of construction 15,000 people were employed with daily
expenditure over £3 million. Ten workers, eight of them British, were
killed during construction between 1987 and 1993, most in the first
few months of boring.
- The Channel Tunnel consists of two rail tunnels and one service
tunnel, each 32 miles (51 kilometres) in length.
- The “Chunnel” connects Folkestone in Kent, England, with Coquelles
in Pas-de-Calais, France.
- Many of the tunnel boring machines used on the Chunnel were as
long as two football fields and capable of boring 250 feet a day.
- At its lowest point, it is 250 feet deep and at 24 miles long, the
tunnel has the longest undersea portion of any in the world.
- When construction began, British and French tunnel workers raced
to reach the middle of the tunnel first. The British won.
- The chalk marl excavated from Chunnel was used to create
Samphire Hoe Park, a 74 acre nature reserve in Kent England.
Surveying undertaken in the 20 years before construction
confirmed earlier speculations that a tunnel could be bored through a
chalk marl stratum. The chalk marl was conducive to tunnelling, with
impermeability, ease of excavation and strength. On the English side
the chalk marl ran along the entire length of the tunnel, but on the
French a length of 5 kilometres had variable and difficult geology. The
tunnel consists of three bores: two 7.6-metre diameter rail tunnels, 30
metres apart, 50 kilometres in length with a 4.8-metre

diameter service tunnel in between. There are also
cross-passages and piston relief ducts. The service
tunnel was used as a pilot tunnel, boring ahead of
the main tunnels to determine the conditions. English
access was provided at Shakespeare Cliff, French
access from a shaft at Sangatte. The French side used
five tunnel boring machines (TBMs), the English side
six. The service tunnel uses Service Tunnel Transport
System (STTS) and Light Service Tunnel Vehicles
(LADOGS). Fire safety was a critical design issue.
Between the portals at Beussingue and Castle Hill the
tunnel is 50.5 kilometres long, with 3.3 kilometres
under land on the French side and 9.3 kilometres on
the UK side, and 37.9 kilometres under sea. It is the
third-longest rail tunnel in the world, behind the Gotthard Base
Tunnel in Switzerland and the Seikan Tunnel in Japan, but with the
longest under-sea section. The average depth is 45 metres below
the seabed. On the UK side, of the expected 5 million cubic metres
of spoil approximately 1 million cubic metres was used for fill at the
terminal site, and the remainder was deposited at Lower Shakespeare
Cliff behind a seawall, reclaiming 74 acres of land. This land was
then made into the Samphire Hoe Country Park. Environmental
impact assessment did not identify any major risks for the project,
and further studies into safety, noise, and air pollution were overall
positive. However, environmental objections were raised over a highspeed
link to London.

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